Whether they are commercial or industrial, indoor environments leave autonomous vehicles with the troubling problem of navigation. Sophisticated machine-control and motion technologies are only as useful as a vehicle’s awareness of its location and the environment around it. To assist autonomous robots in finding their way, Emidio DiGiampaolo and Francesco Martinelli of Italy’s University of L’Aquila designed a passive radio-frequency-identification (RFID) tag and reader technique. Their approach enables autonomous control through RFID-tag placement.

The phase of the RFID tag’s response signals is sensed by an on-board RFID tag reader. An advanced, multihypothesis Kalman filtering technique is used to enhance the performance of the localization—even in low-density tag environments. This technique results in location accuracy within a few centimeters. The key is a high-directivity ad-hoc tag, which is designed to create a stable and geometrically bounded detection region matched with the extended Kalman filter and odometry readings.

Robots equipped with the localization technology and wheel odometers were tested in a variety of indoor environments for robustness. According to the researchers, the localization of the robots saw improvements compared to what has been reported in other literature. Future work developing more optimal tag placement could lead to enhanced localization accuracy. See “Mobile Robot Localization Using the Phase of Passive UHF RFID Signals,” IEEE Transactions On Industrial Electronics, Jan. 2014, p. 365.